A new pipet tip for the prevention of DNA contamination in PCR samples is described. This new tip is adaptable to the universally used pipettor and contains a physical barrier made of a layer of a special nitrocellulose membrane (Biotrace-NT), ion exchange resins, and polypropylene frit. This barrier device should be able to trap any microscopic drops of sizable DNA present in the aerosol of a contaminated pipettor or stray fluid itself. Considering that a DNA molecule should have a minimum size of 10kb to be amplified by PCR, this product will eliminate pipetting "carry-over" problems in PCR procedures. This device will also have the potential of reducing radioactive and protein contamination of pipettor as well as preventing genomic DNA contamination by plasmid or PCR amplified fragments which is a real problem in Southern blot technology for forensic and clinical tests. Furthermore these tips will be more cost effective and convenient than the current positive-displacement pipets used to prevent contamination in PCR work.